Investigating spatial resolution, field sequences and image reconstruction strategies using hybrid phantoms in MPI

Hybrid phantoms allow for measurement-based evaluation of particle samples, reconstruction algorithms and field sequences without need of a Magnetic Particle Imaging (MPI) scanning device. Even dynamic hybrid phantoms can be generated using dynamic magnetic offset fields. Multi-dimensional Magnetic Particle Spectrometers are capable of emulating both hybrid system matrices and hybrid phantoms, which can be reconstructed into images. It is shown that a spatial resolution of few hundred micrometres can be achieved for both one-and multi-dimensional excitation using MPI technology. The spatial resolution of reconstructed images increases when including additional receive channels into the reconstruction process. For multi-dimensional imaging the sine-based Lissajous trajectory outperforms the cosine-based Lissajous trajectory in terms of spatial resolution. Both the high signal to noise ratio of a spectrometer and the versatility of hybrid phantom design will enforce innovative measurement-based research on key parameters for MPI.